The narrative arc you’re likely to hear on this Tuesday in early November is that today begins the yearlong countdown to the 2012 presidential contest. But Tuesday’s slate of off-year elections and ballot measures is laden with its own share of drama. From Maine to Washington, voters in seven states will head to the polls to decide controversial ballot propositions on issues ranging from abortion to collective bargaining, in addition to a smattering of important local races. Here’s a look at the battlegrounds where the most is at stake:

Ohio:

In the wake of Wisconsin’s successful drive to curb collective bargaining for public-employee unions, rookie Republican Governor Scott Walker became a celebrated champion in conservative circles. John Kasich, Walker’s counterpart in the Buckeye State, seems set to suffer a different fate. Big Labor, a perennial Democratic pillar, appears on the brink of a blowout win in its push to repeal a 2011 law rolling back collective-bargaining rights for Ohio public employees.

Tuesday’s ballot measure, known as Issue 2, is a referendum on Senate Bill 5, Kasich’s signature legislation. Stalled by a successful petition drive, the bill hasn’t taken effect, and recent polls suggest it won’t. A recent Quinnipiac poll shows Ohioans poised to reject SB5 by a 25-point margin, and a survey released Sunday by the Democratic firm Public Policy Polling also suggests labor unions are on track for a decisive win after raising more than $30 million in support of the law’s repeal.

Governor Kasich and his supporters say the law, which would prohibit strikes and force public employees to fork over more money to pay for their benefits, is a modest way for teachers, firefighters and cops to do their part in helping to close the state’s budget shortfall. But a collaborative push by labor-allied groups — and the avalanche of cash — has helped turn public opinion against the legislation. Repeal would be a sharp rebuke to Kasich, whose approval ratings are mired near the bottom of the roster of sitting governors. “A big part of it is voters wanting to send a message to John Kasich,” says Tom Jensen, Public Policy Polling’s director. “Rejecting Senate Bill 5 is almost a proxy for the fact that they wish they could do the governor’s race differently.”

While it’s not surprising that nearly all Democrats want to throw out the law, a majority of independent voters and 30% of Republicans do as well. That’s a testament not just to the robust campaign waged by the labor unions fighting the law, but also the political hazards of casting teachers, cops and firefighters — staples of the state’s middle class — as budget-busting bogeymen.

For Ohio conservatives, there’s a bright spot, however: polls suggest that Issue 3, a Tea Party-propelled constitutional amendment that would prohibit government from requiring citizens to purchase healthcare, looks poised to pass.

Mississippi:

While the battle in Columbus is the latest in the ongoing fight over public-employee benefits, the one brewing in Mississippi could usher in an unprecedented victory for the anti-abortion movement. Mississippi voters on Tuesday will decide Initiative 26, a constitutional amendment that would declare human life to begin “at the moment of fertilization.” The amendment would ban abortions even in pregnancies conceived through rape or incest, which would be the most stringent such standard in the country. No state has defined an embryo is a person; similar ballot initiatives have twice failed in Colorado. But the “Personhood amendment” has a solid shot at passage in this staunchly conservative state. A Public Policy Polling survey released Sunday revealed a virtual toss-up, with 45% backing the proposition and 44% opposing it.

The philosophy undergirding the amendment — a belief that abortion is morally wrong, even when performed under extenuating circumstance — alarms even many voters opposed to the practice, says PPP’s Jensen. “The absolutely-no-exceptions nature of the proposal is too much for some people,” he says, noting that nearly 30% of Mississippi Republicans reject the amendment. “Lots of pro-life voters still think some exceptions make sense.” Legal experts, meanwhile, say the amendment’s Achilles Heel is its ambiguity, which a pair of law professors catalogued in a New York Times op-ed. The use of the term fertilization sparked fears that forms of birth control, in vitro fertilization and stem cell research could be banned along with abortion — something proponents deny, though they say the amendment would outlaw the use of the morning-after pill. The measure could also open the floodgates to a raft of legal challenges at all levels of the system. Some prominent Republicans, like the state’s popular outgoing Governor Haley Barbour, have expressed reservations about the proposal’s language. (In the end, Barbour said, he cast an absentee ballot in support of the initiative.)

Despite these concerns, the deciding factor in the amendment’s fate could be turnout, Jensen says. Mississippians are also trekking to the polls on Tuesday to pick a new governor — and the race is shaping up as an easy win for the Republican candidate, lieutenant governor Phil Bryant. Bryant’s Democratic opponent, Johnny DuPree, is African-American, as is 37% of the state. “The higher the black turnout is, especially with a black gubernatorial candidate on the top of the ticket, the more likely [the Personhood amendment] is to be defeated,” Jensen says.

Virginia:

There are no high-profile ballot initiatives there, but President Obama may be keeping an eye on a bellwether battle taking place on the fringes of the Beltway. In 2008, Obama became the first Democrat to win Virginia since Lyndon Johnson — a victory delivered by the party’s redoubts in the D.C. suburbs, a reliable counterweight in an otherwise conservative state. But experts predict that Democratic seats in Northern Virginia are among those poised to flip in the state Senate races on Tuesday. “The odds are strongly in favor of the Republicans taking control of the Senate,” Mark Rozell, a professor of public policy at Virginia’s George Mason University, tells Reuters. That would give the GOP control of each branch of government in Richmond, where they already boast a majority in the House of Delegates and where state’s conservative governor, Bob McDonnell, remains popular.

That result would augur trouble next November for the President. As elsewhere, Virginia’s independents have gravitated toward Republicans amid the ongoing economic turmoil of the past three years, a fact reflected in Obama’s own approval ratings, which sat in the 40s in two October polls. The President trails Mitt Romney in the commonwealth by an average of 3.5 points in an amalgam of polls from the past two months, according to RealClearPolitics — even as Obama has lavished attention on the state, crisscrossing it last month in a bus tour designed to sell his jobs plan. Fending off a Republican onslaught in Virginia will be a heavy lift. If Republicans capture the state Senate, it would be a poor omen for Obama’s prospects of a repeat victory in the state next fall.